Microrobotic photocatalyst on-the-fly: 1D/2D nanoarchitectonic hybrid-based layered metal thiophosphate magnetic micromachines for enhanced photodegradation of nerve agent

Abstract

Micro/nanorobots, deployed to programmable missions, are at the forefront of next-generation machinery and robotics. Here, we present magnetically actuated 2D-microrobot photocatalysts with enhanced photocatalysis due to enhanced mass transfer by photocatalytic on-the-fly microrobot action. The magnetic 2D-microrobots, consisting of layered manganese thiophosphates (MnPS3) and Fe3O4 nanochains, are fabricated by electrostatic assembly, which provides versatile and efficient 1D/2D hetero-dimensional nanoarchitectonic hybridization. The resulting MnPS3-Fe3O4 microrobots are actively propelled by vertical tumbling under a transversal rotating external magnetic field. Particularly, a programmed swarming mode enables local fluid convection and self-stirring, which enhances the photochemical reaction. The promise of swarming 2D-microrobots was shown for enhanced photodegradation of an organic pollutant (Rhodamine B, Rh-B) and the nerve agent chlorpyrifos (CPS); here, MnPS3-Fe3O4 microrobots act like moving 2D photocatalysts, with enhanced degradation efficiency of 10.3% (Rh-B) and 8.8% (CPS) compared to that of static hybrids. The moving 2D photocatalyst and heterodimensional nanoarchitectonic methodology demonstrated here can potentially inspire a variety of highperformance magnetic 2D-micro/nanorobots for catalytic applications.